Fig. 3From: Origin and evolution analysis and genetic characteristics of echovirus 9 in ChinaMaximum likelihood phylogenetic trees were illustrated in (a–d) based on the VP1, P1, P2, and P3 coding regions of the prototype sequence of all EV-B in the GenBank database and the fifteen Chinese E9 strains in this study. Strains isolated from this study were marked with black circles. The scale bars indicate the substitution per site per yearBack to article page